1. Technical Field
This invention generally relates to computer systems, and more specifically relates to apparatus and methods for improving access to data in a computer database by incorporating ontological relationships in a query language and a computer database.
2. Background Art
Database systems have been developed that allow a computer to store a large amount of information in a way that allows a user to search for and retrieve specific information in the database. For example, an insurance company may have a database that includes all of its policy holders and their current account information, including payment history, premium amount, policy number, policy type, exclusions to coverage, etc. A database system allows the insurance company to retrieve the account information for a single policy holder among the thousands and perhaps millions of policy holders in its database.
Data is typically stored in database tables. The tables contain columns and rows of data. The data in the table is related to or associated with other data in corresponding columns and rows. For the example described for insurance companies, the rows of the database may be associated with the name of policy holders, while the columns would be for different pieces of data such as policy number and policy type. In prior art databases, relationships of the data are stored in indexes.
Retrieval of information from a database is typically done using queries. A database query typically includes one or more predicate expressions interconnected with logical operators. A predicate expression is a general term given to an expression using one of the four kinds of operators (or their combinations): logical, relational, unary, and boolean, as shown in FIG. 2. A query usually specifies conditions that apply to one or more columns of the database, and may specify relatively complex logical operations on multiple columns. The database is searched for records that satisfy the query, and those records are returned as the query result.
Data stored in a typical database may include ontological relationships. For use in this specification and claims, an ontological relationship is defined as the hierarchical structuring of knowledge about data by sub categorizing data items according to their essential, relevant or cognitive qualities. Prior art databases do not capitalize on these ontological relationships of data stored in the database.
The data stored in prior art indexes and used to query the database do not store and use ontological relationship information. Information that is stored in one column may be related to information stored in another column, but the difficulty in maintaining these relationships has limited their use. This lack of storing and using ontological relationships of the data limits the database's utility and efficiency. Without a way to capitalize on ontological relationships of data, the full potential of the computer industry to continue to improve efficiency of database performance will be limited.